Vibrational states of polyatomic molecules

[hanicinecm]

Unless I'm missing something in the underlying physics, I think states like '1v1 + 0v2 + 0v3' should be either parsed as '1v1', or raise an exception. This is what happens instead:

In [20]: StatefulSpecies('M 0v1+0v2+0v3')
Out[20]: M ν1+ν2+ν3

In [21]: StatefulSpecies('M 1v1+0v2+0v3')
Out[21]: M ν1+ν2+ν3

In [22]: StatefulSpecies('M 0v1+1v2+0v3')
Out[22]: M ν1+ν2+ν3

In [23]: StatefulSpecies('M 0v1+0v2+1v3')
Out[23]: M ν1+ν2+ν3

In [24]: StatefulSpecies('M 1v1+1v2+1v3')
Out[24]: M ν1+ν2+ν3